At Westminster, the fraught atmosphere intensified on Saturday, with some of Mr Johnson’s supporters claiming that Mr Gove was simply a “suicide bomber” who was being used by allies of Mr Cameron and George Osborne to “take out” their rival, the former London mayor.

Andrea Leadsom Credit:
Rex Features/Rex Features

However, allies of both Mr Gove and Mr Cameron strongly denied that Downing Street had any hand in a plot.

The Prime Minister told friends he was deeply shocked by Mr Gove’s behaviour and felt a sense of sympathy for Mr Johnson.

One friend of the Prime Minister said Mr Cameron was “astounded” by Mr Gove’s actions but recalled how the Justice Secretary had betrayed him in the referendum campaign.

Mr Cameron believes Mr Gove failed to honour a promise that he would not campaign vigorously for Brexit.

The extraordinary feud between Mr Johnson and Mr Gove ended the former mayor’s leadership bid and has damaged the Justice Secretary’s chances of progressing in the contest.

With two leading Brexit campaigners suffering from their bitter personal clash, Mrs Leadsom is quickly emerging as the preferred candidate among Tory grandees and Eurosceptics.

On Saturday, she won the private backing of a senior Thatcherite grandee, as well as public support from Lord Tebbit, and Sir William Cash, the chairman of the Commons EU scrutiny select committee.

Sir William said: “Andrea is the authentic voice for Brexit. She is competent, she is experienced, she has knowledge of the EU issue and she will deliver.”

Lord Tebbit, who served in Thatcher’s Cabinet in the Eighties, said he thought Mrs Leadsom was her political heir. “She has a hinterland of business experience outside, which is something sorely needed these days among members of the House of Commons,” Lord Tebbit said.

“If you look at her background, her beliefs and her record she is essentially a Thatcherite figure. She is the obvious candidate.”

Another senior Tory peer who also worked under Lady Thatcher in the Eighties agreed that she “may be” seen as the heir to the Iron Lady, adding: “I have been very impressed during her performance in the referendum debate. She has been entirely consistent.”

On Monday Mrs Leadsom, 53, will formally launch her campaign for the leadership of the Conservative Party at an event in Westminster.

Her supporters suggest she has already won the private backing of well over 50 MPs, which would put her comfortably in second place behind Mrs May.

In her interview, Mrs Leadsom insists that only a Leave supporter can be trusted to take Britain out of the EU.

She refuses to countenance allowing Mrs May – who has signed up more than 100 MPs in support – to be crowned prime minister unopposed.

She says she is not a “reincarnation” of Lady Thatcher, but is happy to be compared with her.

“I met her a few times. I was always in awe of her and I don’t think people should be in awe of me. I’m just a normal person,” Mrs Leadsom says.

Allowing the Tory party’s 150,000 members the choice between two women would be great to encourage more young girls to consider political careers, she says.

“There is still a sense in our society, a holding back of girls and young women, and I don’t think there should be. To give young women the confidence to think ‘I can do this’ – as Margaret Thatcher did to me – is great.”